Internal combustion engine with positive fuel feeds



H. JUNKE RS July 26, 193;.

INTERNAL COMBUSTION ENGINE WITH POSITIVE FUEL FEEDS 1115a Nov. 25. 1927 //7 yen/or Patented July 26, 1932 PATENT OFFICE- HUGO JUNKERS, OF DESSA'U, GERMANY INTERNAL (JOMIBUS'II ON ENGINE WITH POSITIVE. FUEL FEEDS Application filed November 25, 1927, Serial No. 285,703, and in Germany larch 10, 1927.

' inates jerking.

With this object in mind, I provide, in-

combination with the means for supplying fuel to the engine, for instance, a fuel pump for solid injection, and With the means for varying the delivery of the pump, a regulator which is adapted to automatically adjust the varying means for a predetermined speed of the engine, mechanism such as a pedal lever and its accessories adapted to be operated by the driver of the vehicle for adjusting the regulator for a different speed, for instance, varying the suction in the intake pipe of the engine by means of a throttle which variation in turn influences the regulator, and

means for limiting the response to the regu= lator to the mechanism when the mechanism is operated to adjust the regulator for a 1 higher speed, which means are operatively connected to the mechanism.

In a preferred embodiment of my invention I provide a two-cycle engine which may be a Diesel engine, with a fuel pump for positive injection and with the usual" throttlecontrolled intake pipe for the scavenging pump. The novel system is particularly suitable for'two-cycle engines as the flow of air in their intake pipes is more uniform than the flow in the suction pipes of four-cycle engines to which air is admitted only during each alternate revolution of the crank shaft. At the rear of the throttle I provide a regulator casing which at one side is open to the atmosphere and at'the other side is connected to the intake pipe, and in this casing I provide a member which will be referred to as a vane or oscillating piston so that it will be moved or oscillated by variations of the pressure in the intake pipe. The regulator member is connected to resilient means, for instance, a spring, for counteracting its movement, and also to the fuel pump so that the delivery of the fuel pump is varied in dependency from the variations of the pressure in the intake pipe, and means such as a check is operatively' connected to the throttle for limiting the response of the regulator mem-- ing-up are performed gradually and without jerking.

It is another object of my invention to so design an engine, more especially of the Diesel type, in which the fuel is forced into the cylinder by positive means, (asin the case of solid injection) that the regulation of fuel delivery is effected by controlling means resembling as closely as possible those usually provided for engines of the carbureter type to which the drivers are accustomed. Such controlling means comprise a simple throttle the regulation of which need not be very feeling and which has no complicated and delicate parts. To adapt such a control to positively vfed engines certain additional mechanism is required.

I provide mechanism for the fuel feed by which such feed is regulated in conformity with the requirements of the engine as to speed or power, and Iv combine with this mechanism a throttle in the air-intake pipe of the engine, so that it is operated automatically by controlling the throttle as usual in ordinary motor car engines.

I prefer to connect the regulating mechanism with a measuring fuel pump of known type so that the delivery of the pump per stroke is varied in conformity with the opera tion of the throttle control.

As mentioned, my system is particularly suitable for two-cycle engines for the reason stated, but it is to be understood that I am not limited to the application of my invention to two-cycle engines.

Preferably the feed pump is of the valveless type or controlled by slide valves so that regulator as a reciprocating or an oscillating piston or a diaphragm, the movements of any of these parts being transmitted onto the operating mechanism of the fuel feeding means, which may be a pump or the like.

. Preferably the transmitting members are so constructed as not to exert a considerable reaction on the regulating mechanism, and so as to require only small power for operation so that notwithstanding the small variations of pressure available for the regulation, the transmitting means, such as pistons or the like, need not be made unduly large. This is particularly important in the case of solid injection where the high pressure arising in the fuel feed pump requires considerable power for varying the fuel feed by means of adjustable cams, for the forcing open of valves and the like, considerable reaction on the regulating mechanism being often inevitable.

These condition can be fulfilled by regulating the fuel feed by rotating a control member, for instance the pump pistonitself, as such rotation can be performed with very 7 little expenditure of power, and without any reaction.

In the propulsion of road vehicles the new regulating mechanism involves the important advantage that the regulating or adjusting .force which is simply proportional to the pressure difference acting on the regulating member, to wit, the aforesaid piston, diaphragm or the like, is constant at considerable variations of speed, as distinguished from a centrifugal governor designed for variations of speed within wide limits. For

- instance, if, with the engine running at high speed the throttle which at first is wide open is partly closed, the pressure below normal (vacuum) in the pipe is increased, causing the regulating mechanism to reduce the feed of the pump. This, in turn, reduces the speed of the engine until the same vacuum is reestablished which existed before the regulation (assuming that the charge is substant'ially the same for both conditions of operation). Obviously to the identical vacuum corresponds also the same energy demand of the regulating mechanism and therefore the regulation is effected with absolute reliability for all speeds within the range for which the engine is designed.

The degree of irregularity of the regulating mechanism is also independent from the speed and-is readily influenced by suitably selecting its dimensions or by adjusting its parts, so that the driver can vary the regulation either gradually or rapidly, as desired.

In the accompanying drawing a fuel supply system embodying my invention is illustrated by way of example.

In the drawing,

Fig. 1 is a diagrammatic elevation, partly in section, of a two-cycle engine to which this regulating mechanism is applied, and

Fig. 2 is an elevation, also partly in section, of a modified regulator.

Referring first to Fig. 1, is a twocycle engine with its crank case 26 serving as the scavenging pump. 1 is the air-intake pipe of the scavenging pump 26, 27 is a check valve for the pipe, 2 is the throttle in the'pipe, 3 is a rod connecting the throttle lever with the accelerator pedal 4 and its pull-back spring 6, or any other contrivance for controllin the throttle 2. The parts may of courseie adjusted also by hand.

At a suitable point at the rear of the throttle 2 and in front of the piston 5 of the engine a regulator casing 8 is connected to the intake pipe 1 by means of the pipe 7 9 is an opening in the top wall of the casing connecting it with the atmosphere, and 11 is the regulator member which is shown here as a vane or oscillating piston pivoted in the casing at 12 to rock therein with as small a circumferential clearance as possible. The movements of the piston 11 are transmitted to a rod 14: and a pull-back spring 15 through the medium of a lever 13. 23 is a lever pivoted at one end to the rod 14 and at the other to the piston 21 of a fuel feed pump to which fuel is supplied through a port 22 from a tank 28. The pump is of the valveless type, the piston 21 itself regulatingthe quantity of fuel admitted to the pump by alternately covering and uncovering the passage 22.

The operation of the pump is effected from a pulley or sprocket 29 on the crank shaft of the engine through the medium of a belt or chain 39 and a pulley 40 on a crank shaft 41. The crank of this shaft is connected with the lever 23 by a connecting rod 25 so that the piston 21 of the pump 20 is reciprocated upon rotation of the shaft 41, and its stroke is.varied by the rod 14 displacing the fulcrum of the lever 23.

is a lever on the shaft of thethrottle 2 and 31 is a rod or check fulcrumed to the lever and adapted to act from below with its free end 32 on the lever-13 of the oscillating piston 11. 33 is a guide in which the check 31 is mounted to slide.

Assuming the engine to run under no-load conditions and at comparatively low speed, the throttle 2 is nearly closed and the delivery of the fuel pump 20 is correspondingly small. If it is desired to speed up the engine the accelerator 4 is operated in the direction of the arrow aso as to open the throttle 2 the two sides of the member 11 in the regulator casing 8-so that the spri'ng15 pulls down the lever 13 as indicated by the .arrowb, and raises the member 11. The pivot about which lever 23 rocks is thereby displaced so as to increase the delivery of the pump 20. The speed of the engine is increased in proportion until the initial vacuum conditions in the intake pipe-have been re-established by the increased inflow of air.- The regulator has now been adjusted for the new speed, and its member 11 in turn adjusts the lever 23 so that the engine will run on at this speed.

It 's not desirable that the speeding-u should be effected too rapidly, that is, the response of the regulator member 11 to the reduction of the vacuum in the intake pipe by the throttle 2 must be limited. This is effected automatically by the check 31 which is lowered in proportion as the accelerator 4 is rotated in'the direction of the arrow (1. When the vacuum in the intake pipe is reduced by further opening the throttle 2, the piston 11 tends to set the pump 20 for maximum feed, but is restrained by the end 32 of the rod 31 which recedes only in proportion to the movement of the accelerator 4, so that if the accelerator 4 is operated gradually the pump feed is also only increased gradually and rapid acceleration and jerking are eliminated, the car being sped-up smoothly. The same occurs when the engine is started.

The rod or check 31 might also act directly on the mechanism controlling the pump 20.

In this case rod 14 and lever 13 must be designed with a certain lost motion so as to enable the regulator to reduce the pump feed but not to increase it beyond the extent for which the accelerator 4 has been adjusted.

When it is desired to reduce the engine speed the accelerator 4 is allowed to rotate against the arrow a under the action of its pull-back spring 6. The throttle 2 restricts the free-sectional area of the intake pipe 1, and increases the vacuum therein. The member 11 in the regulator casing 8 now descends,

rotating the lever 13 against the arrow b and displacing the pivot of the lever 23 so as to reduce the delivery of the fuel pump 20. The engine now slows down until the initial vacuum has been re-established in the intake pipe 1 and the engine runs at the reduced speed.

The rotation of the lever 13 against the ar' inder 42. Thepiston 43 is connected to the arm 44 of a double-armed lever 13, 44 by a rod 46. The lever 13, 44 is pivotally mounted at 12 on a bracket 45 which is secured to or cast integral with the cylinder 42. The arm 13 of the double-armed lever is connected to the rod 14 and the pull-back spring 15, as described withreference to Fig. 1. he piston 43 and the arm 44 to which it is connected by the rod 46, replaces the oscillating piston or vane 11 in Fig. 1 and therefore the operation of the regulator is obviously the same as described. for the arrangement shown in Fig. 1, I

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

I claim 1. A fuel-supply system for internal com.- bustion engines comprising means for supply ing fuel to the engine, means for varying the fuel supply, a regulator adapted to automatically adjust said varying means for a predetermined speed'of the engine, mechanism for adjusting said regulator for a different speed, and means operatively connected to said mechanism for limiting the response of said regulator to said mechanism when the latter is operated to adjust said regulator for a higher speed.

2. A fuel-supply system for internal combustion engines comprising means for supplying fuel to the engine, means for varying 3 ferent speed, and means positively connected to said mechanism for limiting the response of said regulator to said mechanism when the latter is operated to adjust said regulator for a higher speed.

3. A fuel-supply sy em for internal com- 7 bustion engines comprising means for supplying fuel to the engine, means for varying the fuel supply, a regulator adapted to automatically adjust said varying means for a predetermined speed of the engine, mechanism for adjusting said regulator for a different speed, and a check operatively connected to said mechanism for limiting the response of said regulator to said mechanism when the latter is operated to adjust said regulator for a higher speed. I

4. A fuel-supply system for internal combustion engines comprising positively acting means for supplying fuel to the engine. means for varying the fuel supply, a regulator adapted to automatically adjust said varying means for a predetermined speed of the engine, mechanism for adjusting said regulator for a difierent speed, and means operatively connected to said mechanism for limiting the response of said regulator to said mechanism when the latter is operated to adjust said regulator for a higher speed.

5. A fuel-supply system for internal com bustion engines comprising a fuel. pump adapted to beoperated from said engine, means for varying the delivery of said pump, a regulator adapted to automatically adjust said varying means forapredetermined speed of the engine, mechanism for adjusting said regulator for a different speed, and means operatively connected to said mechanism for limiting the response of said regulator to said mechanism when the latter is operated to adjust said regulator for a higher speed.

6. A fuel-supply system for internal combustion engines equipped with an air-intake pipe and means for throttling the air intake, comprising a casing connected to said pipe at a point to the rear of said throttling means, a member in said casing adapted to be moved by variations of the pressure in said intake pipe, resilient means adapted to counteract the movement of said member, means for supplying fuel to the engine, means connected to said member and to said fuel-suppl ing means for varying the delivery of said uelsupplying means in dependency from the variations of the pressure in said air-intake pipe, and means operatively connected to said throttling means for limiting the response of said member to the influence of said throttling means when said throttling means is moved in the opening direction.

7. A fuel-supply system for internal combustion engines equipped with an air-intake pipe andmeans for throttling the air intake, comprising a casing connected to said pipe at apoint to the rear of said throttling means, a member mounted to reciprocate in said casing adapted to be moved by variations of the pressure in said intake pipe, resilient means adapted to counteract the movement of said member, means for supplying fuel to the engine, means connected to said member and to-said fuel-supplying means for varying the delivery of said fuel-supplying means in dependency from the variations of the pressure in said air-intake pipe, and means operatively connected to said throttling means for limiting the response of said member to the influence of said throttling means when said throttling means is moved in opening direction.

8. A fuel-supply system for internal combustion enginesequipped with an air-intake pipe and means for throttling the air intake, comprising a casing connected to said pipe at a point to the rear of said throttling means, a member mounted to oscillate in said casing adapted to be moved by variations of the pressure in said intake pipe, resilient means adapted to counteract the movement of said member, means for supplying fuel to the engine, means connected to said member and to said fuel-supplying means for varying the delivery of said fuel-supplying means in dependency from the variations of the pressure in said air-intake'pipe, and means operatively connected to said throttling means for limiting the response of said member to the influence of said throttling means when said throttling means is moved in the opening direction.

9. A fuel-supply system for internal combustion engines equipped with an air-intake pipe and means for throttling the air intake, comprising a casing connected to said pipe at a point to the rear of said throttling means, a member in said casing adapted to be moved by variations of the pressure in said intake pipe, resilient means adapted to counteract the movement of said member, a fuel pump adapted to be operated from said engine, means operatively connected to said member for varying the delivery of said fuel pump in dependency from the variations of the pressure in said air-intake pipe, and means operatively connected to said throttling means for limiting the response of said member to the influence of said throttling means when said throttling means is moved in the opening direction. v

10. A fuel-supply system for internal combustion engines equipped with an air-intake pipe and means for throttling the air intake, comprising a casing connected to said pipe at a point to the rear of said throttling means, a member in said casing adapted to be moved by variations of the pressure in said intake pipe, resilient means adapted to counteract the movement of said member, means for supplying fuel to the engine, means connected to said member and to said fuel-supplying means for varying the delivery of said fuelsupply means in dependency from the variations of the pressure in said air-intake pipe, and means operatively connected to said throttling means for limiting the response of said member to the influence of said throttling means in proportion to the displacement of said throttling means when said throttling means is moved in the opening direction.

11. A fuel-supply system for internal combustion engines equipped with an air-intake pipe and means for throttling the air intake, comprising a casing connected to said pipe at a point to the rear of said throttling means. an oscillation piston in said casing adapted to be moved by variations of the pressure in said intake pipe, resilient means adapted to counteract the movement of said piston, means for supplying fuel to the engine, means connected to said piston and to said fuelsupplying means for varying the delivery of said fuel-supplying means in dependency from the variations of pressure in said airintake pipe, a lever operatively connected to said oscillating piston, and a check operatively connected to said throttling means and adapted to cooperate with said lever for limiting the response of said member to the influence of said throttling means when said throttling means is moved in the opening direction. L

12. A fuel-supply system for internal combustion en es for driving vehicles and equipped with an air-intake pipe and means b adapted to be operated from the drivers seat for throttling the air intake, comprising a casing connected to said pipe at a point to the rear of said throttling means, a member in said casing adapted to be moved by variations of the pressure in said intake pi resilient means adapted; to counteract t e movement of said member, a 'fuel pump adapted to be operated from said engine,

means operatively connected to said member for varying the delivery of said fuel pump in dependency from the variations of the pressure in said air-intake pipe and means operatively. connected to said throttling means for limiting the res use of said memher to the influence of saifi throttlin means when said throttling means is mov in the opening direction.

In testimony whereof I afiix my signature.

HUGO JUNKE S. 

